The President's Address. 37 



art, constructed for himself a camera box^ travelling arrange- 

 ments for micro-photographs, and with a good achromatic 

 lens, manufactured by Ross, set to work with his usual per- 

 severance and industry to take the portraits of all his relatives 

 and friends, scientific or not, the liberal distribution of which 

 among his large circle of acquaintances afforded him un- 

 alloyed pleasure. The Society's museum is enriched by his 

 liberality with micro-photographs of some sixteen of its 

 members. 



Several other short notices from our deceased member 

 have also appeared in the pages of the ' Quarterly Journal of 

 Microscopical Science,' as " On thin glass Covers" (vol. i, 

 p. 141), "On Micrometers and Micrometry^' (vol. iv, p. 241), 

 " On Microscopical Photographic Portraits" (vol. vii, p. 122). 

 He also undertook to oblige his friend, the late Dr. Pereira, 

 with the measurement of the starch granules of various amy- 

 laceous substances for the last edition of his ' Elements of 

 Materia Medica' then in preparation, twenty-five of which 

 have been published in that work. 



One of the greatest improvements in the microscope as a 

 working instrument was that carried out by Mr. Jackson in 

 the construction of the continuous bar, supporting the body 

 of the instrument above the stage, and carrying a small 

 secondary body below, the whole bar being planed from end 

 to end on one level, and with rack ; this secondary body 

 carrying the achromatic or other condenser, polarising prism, 

 dark well, &c. In this way the axis of the instrument is per- 

 fectly continuous, and no centering or adjustment is required. 



Three sets of castings were made from the patterns which 

 he had constructed, two of which were given to his friends, 

 Mr. Alfred White and the late Mr. Greening; and the 

 patterns were then transferred to Messrs. Smith and Beck, 

 and exist in the present form of their No. 1 instrument. 



In 1858 Mr. Jackson was elected one of the managers of 

 the London Institution. 



In his own profession in mechanical surgery he exhibited 

 considerable tact and skill ; and although such requirements 

 were seldom brought into action, yet it was a source of 

 great delight to him if he could by some simple contrivance 

 alleviate the sufferings of his patients, and thus facilitate 

 their cure. One of the last undertakings of his life was the 

 production of a very simple and most efficient contrivance for 

 reducing dislocations of the shoulder-joint — an operation at 

 times, in very muscular subjects, very difficult to perform. 



His quiet and unassuming manners, his clear and upright 

 mind, rendered him generallv K<>i*ved ; and the readiness 



